1. Field of the Invention
The invention relates to a cutting or hewing roll, the cutting length of which is pivotally adjustable.
2. Description of the Prior Art
For the purpose of increasing the cutting length of cutting rolls it is already known to provide roll sections which are telescopically shiftable in an axial direction, i.e. which are shiftable along the axis of rotation of the cutting roll and being arranged for being fixed in its respective adjusted position. Such telescopically expandable and retractable roll sections require a relatively expensive drive means and the support of such telescopically expandable parts must be designed in a manner which, on the one hand, permits axial shifting movement and which, on the other hand, reliably provides for a positive rotary connection with the remaining parts of the roll. On account of the required shiftability in axial direction, the positive rotary connection must be given a certain amount of play, which results in a high wear of such driving connections. The variability of the cutting width (i.e. of cutting roll effective length) primarily serves the purpose to improve the maneuvrability of the whole machine and shall provide the possibility to prevent any hindrance by already positioned consolidating props or the like when travelling along curves of smaller radius of curvature or through more narrow drift sections of a mine.
Known devices of the initially mentioned type, in which roll parts are shiftable in direction of the axis of rotation of the cutting roll or hewing roll and are supported for positive rotary connection with a roll part which is part non-shiftably supported, may, for example, be learned from U.S. Pat. No. 4,172,616.